Sewing machine safety device



May'lO, 1938. H. GUNTHER.

SEWING' MACHINE SAFETY DEVICE Filed July *3,v 1936 2 Sheets-Sheet 1 May10, 1938. H.. GUNTHER sEwING MACHINE SAFETY DEVICE Filed July 3, 195s 2Sheets-Sheet 2 y?? @EE fil Patented May 10, 1938 UNITED STATES PATENToEFlcE 2,116.ss9 SEWING MACHINE SAFETY DEVICE Hermann Gunther, lizabeth,N. J., assignor to- The Singer Manufacturing Company, Elizabeth, N. I.,a corporation of New Jersey Application July 3, 1936, Serial No. 88,737

11 Claims.

One of the objects of this invention is to provide an improved safetydevice which will prevent the Work-clamp from being raised until thepredetermined number of stitch-forming cycles has been completed, theusual trimmer mechanism operated to sever the threads, and the machinehas come to rest.

Another object of this invention is to provide ay safety device whichmay be 'readily applied to machines already in use and which ischaracter-.

ized by its compactness, durability and simplicity, and its provisionsfacilitating its accurate assembly and incorporation in existingmachines.

A still further object of this invention is to provide an improvedsafety device which will prevent the presser-bar lifting lever frombeingraised when the machine begins its cycle of operations or to prevent themachine from being started until theapresser-bar lifting lever is in itsnormal position. f

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forthand illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention' and the advantages attained thereby will bereadily understood by those skilled in the art.

Figure 1 is a rear side elevation of a sewing machine showing myimproved safety device applied thereto. l Y

Figure 2 is a sectional view ofthe controlling `cam-and disk, takenalong the line 2-2 of Figure l.

locking disk or ring. A

As represented, the machine is constructed with a frame comprising/thecylinder-bed or Work-arm I from which rises the standard 2 carrying abracket-arm ril terminating in a hollow within the free end of thehollow .cylinder-bed I. y

The work is adapted to be clamped between the *upper and lower membersof a work-holder Figure 3 isa perspective view of the clampmain-shaft 5.

which, in the particular embodiment illustrated, is moved to and froover the work-support to position the stitches in accordance withthe'desired pattern. The present work-holderis of the general typedisclosed in the patent to Barron No. 1,205,317, of November 21, 1916',and comprises the sliding bar 8 carrying a work-supporting plate 9 atthe end adjacent the stitch-forming mechanism. Mounted on the bar 8 is abracket Il having at itsfree end a head II which carries the usualpresser-bar I2 terminating in a workclamp or worl-holder I2' which isspring urged towards the plate 9. Projecting forwardly from thepresser-bar I2 through a slot in the face of the head II is a rod I3 theextremity of which lies above and in the path of vertical movement ofthe arm I4 of a bracket-piece xed to the lower end of the usualwork-holder lifting bar I5 carried by the head 4.

The work-holder is moved longitudinally of the Work-arm I by means ofthe usual cam slot 5|! in the inner face of the controller cam wheel I6(see Fig. 2), which imparts rocking motion to a lever II. The motion ofthe lever Il is communicated in a well known manner to the verticalpostv I8.n rising from the rear end of the bar. The workholde'r isvibrated laterally of the work-arm I about the post Il as a pivot bymeans of the usual connections with the cam slot I9 in the outer face ofthe controller cam I6. The connections include the bell-crank lever 20,pitman 2|", rockshaft 22 and arm 23. 'I'he means for impartinglongitudinal and lateral movements to the workthread-cutter, not shown,for cutting the threads usual belt shifting guide arm 4I rigid with it.

The stop-lever 4I) carries A the Spring pressed plunger rod 42 adaptedto engage the Stopping cam 43 iixed to the pulley 44 which is xed to theThe cycle of operation of the machine is Started by actuation of theangle lever 45 which causes the lever 40 to move to the right as Y idlerpulley 46 to the fast pulley 44 thereby starting the cycle of-operation.The stop-lever 40 is locked in running position (the position showninlatch 48 mounted upon the frame 49 by means of the fulcrum screw stud 5land is adapted to be tripped for disengagement of the stop-lever bymeans of the tripping stud 52 carried upon the inner face of thecontroller cam i6. The threadcutting and stop-motion mechanism are fullydescribed in the said Horton patent and further description is deemedunnecessary.

It will be understood that a machine. of the present type when trippedinto action, automatically performs a definite series of operationsunder control of the cam l and is then brought to rest by thestop-motion device. Operators of these machines often anticipate themoment that the cycle of operation is completeand press on a treadle'which, in practice, is connected by a chain to the usual presser-barlifting lever which is pivoted to the arm 3 at 25. The 'operatorsometimes presses on the treadle and raises the presser-bar andwork-holder before the machine has come to rest and when this occurs thethread or needle may be broken, o r the thread-cutter may not have hadtime to operate and sever the thread close to the underside of the work.To make it impossible for the operator to raise the presser-bar bypressing on the treadle before the machine has come to rest I haveprovided the machine with an attachment which may be readily xed toexisting machines. The attachment comprises a ring 2l detachably securedto the outer face of the controller cam it by the screws 28 and ahardened steel ringer 3l which is adjustably secured to a substitutepresser-bar lifting lever 2&3 by the set screw 32, the lever 2d having atreadle-chain lug 24. The controller cam is rotated 180 for eachoperative cycle of the machine and the ring 21 is formed with twodiametrically opposite notches 29 and 30 in its l periphery with whichthe finger 3l alternately registers when the machine is in stopposition.

' It Ywill be obvious from the foregoing that the nger 3l normally ridesupon the periphery of the ring 2l and the ring 21 is so timed with theoperation of the machine that the finger overlies one of the notches 29or 30 only when the machine is in stop position and. therefore, thelever 24 can only be operated to lift the presserbar when the machinehas come to rest.

The ring 2l is made of cast iron and to prevent excessive wear on theedges of the notches 29 and 3B and also to provide means for accuratelytiming the point in the cycle of operation of the machine at which thelever 24 may be operated, hardened steelwear plates 33 are adjustablysecured in grooves 3G in the periphery actuated during the initialstitch-forming cycles and before theiinger 3l rides out of the notch thefree end of the lever 24 may be extended to a. point at which it willoverlie the belt-shifting guide arm 4I when this arm is in the positionindicated in dotted line in Fig. 1. As previously described the anglelever 45 is actuated to move the stop-lever 40 and belt-shifting arm 4lto -the right as viewed in Fig. 1, and it will be obvious that if thelever 24 is depressed so as to raise the presser-bar I2 the free end 41of the lever will prevent the beit-shifting arm 4| and stoplever 40 frombeing shifted to the dotted line position to start the machine. On theother hand, if the lever 24 is in the position shown in Figure 1 thenthe stop-lever 40 and belt-shifting arm 4i may be moved to the dottedline position to start the machine and it will be noted that when thearm 4I is in the position shown 1n dotted lines the lever 24 is lockedso that it cannot be actuated to raise the work-clamp. Just prior to theend ofthe cycle of operation the stop-lever 40 and arm 4I areautomatically shifted back to the full line position and therefore, thearm di is moved out of the way of the end 4l of the arm 24. However, thefinger 3l is riding on the disk 21 at this point inthe cycle andconsequently the lever 24 cannot beactuated until the nger 3l overliesone of the notches 29 or 30 in the ring 2l, at which time the machinehas come to rest.

It will be apparent that the above described construction may bemodified so that operation of the lever 24 is prevented by other movablep of work-clamp it will be obvious that other types" of work-clamps maybe used and my improved safety device may be embodied in various typesof sewing machines that perform a definite series of operations and thencome to rest.

Having thus set forth the nature of the invention, what I claim hereinis:-

1. In a sewing machine adapted toperform a definite series of operationsin combination stitchforming mechanism including a reciprocatory needle,a shiftable work-holder, a cam for con trolling the shifting movementsof said workholder, manual means for raising and lowering said.work-holder and means carried by said cam for preventing saidwork-holder from being raised until the machine has completed its seriesof operations.

2. In asewing machine adapted to perform a denite series of operations,in combination, stitch-forming mechanism including a reciprocatoryneedle, a work-holder, means for causing said needle and work-holder tovibrate relative to each other, a cam for controlling the series ofoperations of the machine, means for raising said work-holder, and meansunder control of said cam for preventing the work-holder from beingraised until the machine has completed its series of operations.

3. An attachment for a sewing machine having a work-holder, means forraising said workholder, and a rotatable cam, comprising a ringattachable to said cam 'and mechanism interposed between said ring andsaid raising means for preventing said raising means being operatedexcept at predetermined intervals.

4. An attachment for sewing machines having a rotatable element, awork-holder and means for. raising said work-holder, comprising amemtory needle, a. stop-motion device, a cam for con-.- n trolling thecycleof-operation of the machine:l l a work-holder, a lever for raisingand lowering said'work-holder, a member on said cam and means under thecombined control of said stopmotion device and said member forpreventing thelever from being actuated except at predetermined times toraise the work-holder.

6. In a sewing machine adapted to perform a definite series ofoperations, in combination, stitch-forming mechanism including areciprocatory needle, a stop-motion device, a cam for controlling saidstop-motion device, a work-holder, means for raising said work-holder,means under control of said stop-motion device for preventing saidwork-holder vfrom being raised at the beginning of the cycle ofoperation and a member carried by said cam for preventing saidworkholder from being raised until the machine has completed its cycleof operation and come to rest.

7. An attachment for a sewing machine having a work-holder, a lever forraising said workholder, and a controller cam, comprising a fingercarried by said lever and a ring adapted lto be secured to said cam,said ring having a plurality of notches in its periphery which areadapted to underlie the finger on said lever at predetermined times,whereby said lever may be actuated to raise said work-holder.A

8. A safety device for sewing machines having a work-holder, a lever forraising said workholder and a cam for controlling the operation of themachine, comprising a ring actuated by said cam and having one or morenotches in its.

outer periphery. and a linger adiustably secured -a lever for raisingsaid work-holder, means shiftable into the path of movement of saidlever at the beginning of a series of operations to prevent saidwork-holder from being raised, and a second means for preventing saidlever from being raised until the machine has come to rest.

10. In a sewing machine adapted to perform a definite series ofoperations in' combination,

stitch-forming mechanism including a reciproca# tory needle, awork-clamp, a stop-motion devicel including a pivoted lever, and a clamplifting lever having interengaging relation witi said lever. 11. In asewing machine adapted to perform a definite series of operations, incombination, stitch-forming mechanism including a reciprocatory needle,a work-clamp, a stop-motion device including, a pivoted member, and aclamp-lifting lever, said member and said lever being so constructed andarranged that each is movable into the path of movement of the other.

HERMANN GNTHER.

